DataSourceDesigner Classe

Definição

public ref class DataSourceDesigner : System::Web::UI::Design::ControlDesigner, System::Web::UI::Design::IDataSourceDesigner

public class DataSourceDesigner : System.Web.UI.Design.ControlDesigner, System.Web.UI.Design.IDataSourceDesigner

type DataSourceDesigner = class
    inherit ControlDesigner
    interface IDataSourceDesigner

Public Class DataSourceDesigner
Inherits ControlDesigner
Implements IDataSourceDesigner

Herança

Object

ComponentDesigner

HtmlControlDesigner

ControlDesigner

DataSourceDesigner

Derivado

System.Web.UI.Design.WebControls.EntityDataSourceDesigner

System.Web.UI.Design.WebControls.LinqDataSourceDesigner

System.Web.UI.Design.WebControls.ObjectDataSourceDesigner

System.Web.UI.Design.WebControls.SqlDataSourceDesigner

Implementações

IDataSourceDesigner

Exemplos

O exemplo de código a seguir mostra como usar um controle de fonte de dados personalizado com várias outras classes personalizadas pequenas, conforme listado na tabela a seguir.

Depois de compilar o exemplo de código, abra a página .aspx no modo Design e defina a DataSourceID propriedade como a ID do controle de fonte de dados personalizado.

using System;
using System.Data;
using System.Security.Permissions;
using System.Collections;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.Design;
using System.Web.UI.Design.WebControls;
using System.ComponentModel;
using System.ComponentModel.Design;

namespace ASPNet.Design.Samples_CS
{
    [Designer(typeof(CustomDataSourceDesigner)),
        ToolboxData("<{0}:CustomDataSource runat=\"server\"></{0}:CustomDataSource>")]
    public class CustomDataSource : ObjectDataSource
    {
        private ObjectDataSourceView _view = null;
        private string _defaultViewName = "BookList";

        public CustomDataSource() : base() { }

        // Gets a view by name
        protected override DataSourceView GetView(string viewName)
        {
            // This data source only allows one view
            if (viewName != _defaultViewName)
            {
                return null;
            }
            else if (_view == null)
            {
                _view = new CustomDataSourceView(this, 
                    _defaultViewName, HttpContext.Current);
            }

            return _view;
        }

        // Gets a list of view names for this class
        protected override ICollection GetViewNames()
        {
            ArrayList ar = new ArrayList(1);
            ar.Add(_defaultViewName);
            return ar as ICollection;
        }
    }

    // The runtime data source view
    public class CustomDataSourceView : ObjectDataSourceView
    {
        private ArrayList _data = null;

        public CustomDataSourceView(CustomDataSource owner, 
            string viewName, HttpContext context)
            : base(owner, viewName, context)
        {
            owner.SelectCountMethod = "GetCount";
        }

        // This method would typically get a set of live data  
        // rather than create some dummy data
        protected override IEnumerable ExecuteSelect(
            DataSourceSelectArguments arguments)
        {
            if (_data == null)
            {
                // Create a set of runtime fake data
                _data = new ArrayList();
                _data.Add(new BookItem("ID_1", "Runtime Title 01"));
                _data.Add(new BookItem("ID_2", "Runtime Title 02"));
                _data.Add(new BookItem("ID_3", "Runtime Title 03"));
            }

            return _data as IEnumerable;
        }

        // Allow getting the record count
        public override bool CanRetrieveTotalRowCount
        {
            get { return true; }
        }

        // Returns the number of records in the current set of data
        public int GetCount()
        {
            if (_data == null)
                return 0;
            else
                return _data.Count;
        }
        
        // Do not allow deletions
        public override bool CanDelete
        {
            get { return false; }
        }
        // Do not allow insertions
        public override bool CanInsert
        {
            get { return false; }
        }
        // Do not allow paging
        public override bool CanPage
        {
            get { return false; }
        }
        // Do not allow sorting
        public override bool CanSort
        {
            get { return false; }
        }
        // Do not allow updating
        public override bool CanUpdate
        {
            get { return false; }
        }
    }

    // A class to define each record of the data
    public class BookItem
    {
        private string _id;
        private string _title;

        public BookItem(string id, string title)
        {
            _id = id;
            _title = title;
        }

        public string ID
        {
            get { return _id; }
        }
        public string Title
        {
            get { return _title; }
            set { _title = value; }
        }
    }

    // Custom designer for the CustomDataSource control.
    public class CustomDataSourceDesigner : DataSourceDesigner
    {
        private CustomDataSource _control;
        private string _defaultViewName = "BookList";
        private CustomDesignDataSourceView _view = null;

        // Initialize the designer
        public override void Initialize(IComponent component)
        {
            base.Initialize(component);
            _control = (CustomDataSource)Component;
        }

        // Get a view
        public override DesignerDataSourceView GetView(string viewName)
        {
            if (!viewName.Equals(_defaultViewName))
                return null;

            _view ??= new CustomDesignDataSourceView(this,
                _defaultViewName);

            return _view;
        }

        // Get a list of view names
        public override string[] GetViewNames()
        {
            return new string[] { "BookList" };
        }

        // Do not allow refreshing the schema
        public override bool CanRefreshSchema
        {
            get { return false; }
        }
        // Do not allow resizing
        public override bool AllowResize
        {
            get { return false; }
        }
    }

    // A design-time data source view
    public class CustomDesignDataSourceView : DesignerDataSourceView
    {
        private ArrayList _data = null;

        public CustomDesignDataSourceView(
            CustomDataSourceDesigner owner, string viewName)
            : base(owner, viewName)
        {}

        // Get data for design-time display
        public override IEnumerable GetDesignTimeData(
            int minimumRows, out bool isSampleData)
        {
            if (_data == null)
            {
                // Create a set of design-time fake data
                _data = new ArrayList();
                for (int i = 1; i <= minimumRows; i++)
                {
                    _data.Add(new BookItem("ID_" + i.ToString(),
                        "Design-Time Title 0" + i.ToString()));
                }
            }
            isSampleData = true;
            return _data as IEnumerable;
        }

        public override IDataSourceViewSchema Schema
        {
            get { return new BookListViewSchema(); }
        }

        // Allow getting the record count
        public override bool CanRetrieveTotalRowCount
        {
            get { return true; }
        }
        // Do not allow deletions
        public override bool CanDelete
        {
            get { return false; }
        }
        // Do not allow insertions
        public override bool CanInsert
        {
            get { return false; }
        }
        // Do not allow updates
        public override bool CanUpdate
        {
            get { return false; }
        }
        // Do not allow paging
        public override bool CanPage
        {
            get { return false; }
        }
        // Do not allow sorting
        public override bool CanSort
        {
            get { return false; }
        }
    }

    // A custom View Schema class
    public class BookListViewSchema : IDataSourceViewSchema
    {
        public BookListViewSchema()
        { }

        // The name of this View Schema
        public string Name
        {
            get { return "BookList"; }
        }

        // Build a Field Schema array
        public IDataSourceFieldSchema[] GetFields()
        {
            IDataSourceFieldSchema[] fields = new IDataSourceFieldSchema[2];
            fields[0] = new CustomIDFieldSchema();
            fields[1] = new CustomTitleFieldSchema();
            return fields;
        }
        // There are no child views, so return null
        public IDataSourceViewSchema[] GetChildren()
        {
            return null;
        }
    }

    // A custom Field Schema class for ID
    public class CustomIDFieldSchema : IDataSourceFieldSchema
    {
        public CustomIDFieldSchema()
        { }

        // Name is ID
        public string Name
        {
            get { return "ID"; }
        }
        // Data type is string
        public Type DataType
        {
            get { return typeof(string); }
        }
        // This is not an Identity field
        public bool Identity
        {
            get { return false; }
        }
        // This field is read only
        public bool IsReadOnly
        {
            get { return true; }
        }
        // This field is unique
        public bool IsUnique
        {
            get { return true; }
        }
        // This field can't be longer than 20
        public int Length
        {
            get { return 20; }
        }
        // This field can't be null
        public bool Nullable
        {
            get { return false; }
        }
        // This is a Primary Key
        public bool PrimaryKey
        {
            get { return true; }
        }

        // These properties do not apply
        public int Precision
        {
            get { return -1; }
        }
        public int Scale
        {
            get { return -1; }
        }
    }
    
    // A custom Field Schema class for Title
    public class CustomTitleFieldSchema : IDataSourceFieldSchema
    {
        public CustomTitleFieldSchema()
        { }

        // Name is Title
        public string Name
        {
            get { return "Title"; }
        }
        // Type is string
        public Type DataType
        {
            get { return typeof(string); }
        }
        // This is not an Identity field
        public bool Identity
        {
            get { return false; }
        }
        // This field is not read only
        public bool IsReadOnly
        {
            get { return false; }
        }
        // This field is not unique
        public bool IsUnique
        {
            get { return false; }
        }
        // This field can't be longer than 100
        public int Length
        {
            get { return 100; }
        }
        // This field can't be null
        public bool Nullable
        {
            get { return false; }
        }
        // This is not the Primary Key
        public bool PrimaryKey
        {
            get { return false; }
        }

        // These properties do not apply
        public int Precision
        {
            get { return -1; }
        }
        public int Scale
        {
            get { return -1; }
        }
    }
}

Imports System.Data
Imports System.Security.Permissions
Imports System.Collections
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.Design
Imports System.Web.UI.Design.WebControls
Imports System.ComponentModel
Imports System.ComponentModel.Design

Namespace ASPNet.Design.Samples_VB
    <Designer(GetType(CustomDataSourceDesigner)), _
        ToolboxData("<{0}:CustomDataSource runat=""server""></{0}:CustomDataSource>")> _
    Public Class CustomDataSource
        Inherits ObjectDataSource

        Dim _defaultViewName As String = "BookList"
        Dim _view As ObjectDataSourceView = Nothing

        Public Sub New()
            MyBase.New()
        End Sub

        ' Gets a view by name
        Protected Overrides Function GetView(ByVal viewName As String) As DataSourceView
            ' This data source only allows one view
            If Not (viewName.Equals(_defaultViewName)) Then
                Return Nothing
            ElseIf IsNothing(_view) Then
                _view = New CustomDataSourceView(Me, _
                    _defaultViewName, HttpContext.Current)
            End If

            Return _view
        End Function

        ' Gets a list of view names for this class
        Protected Overrides Function GetViewNames() As ICollection
            Dim ar As New ArrayList()
            ar.Add(_defaultViewName)
            Return CType(ar, ICollection)
        End Function

    End Class

    ' The runtime data source view
    Public Class CustomDataSourceView
        Inherits ObjectDataSourceView

        Dim _data As ArrayList = Nothing

        Public Sub New(ByVal owner As CustomDataSource, ByVal viewName As String, ByVal context As HttpContext)
            MyBase.New(owner, viewName, context)
            owner.SelectCountMethod = "GetCount"
        End Sub

        ' This method would typically get a set of live data
        ' rather than create some dummy data
        Protected Overrides Function ExecuteSelect(ByVal arguments As DataSourceSelectArguments) As System.Collections.IEnumerable
            If (IsNothing(_data)) Then
                _data = New ArrayList()
                _data.Add(New BookItem("ID_1", "Runtime Title 01"))
                _data.Add(New BookItem("ID_2", "Runtime Title 02"))
                _data.Add(New BookItem("ID_3", "Runtime Title 03"))
            End If
            Return CType(_data, IEnumerable)
        End Function

        ' Allow getting the record count
        Public Overrides ReadOnly Property CanRetrieveTotalRowCount() As Boolean
            Get
                Return True
            End Get
        End Property

        ' Returns the number of records in the current set of data
        Public ReadOnly Property GetCount() As Integer
            Get
                If IsNothing(_data) Then
                    Return 0
                Else
                    Return _data.Count
                End If
            End Get
        End Property
        ' Do not allow deletions
        Public Overrides ReadOnly Property CanDelete() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow insertions
        Public Overrides ReadOnly Property CanInsert() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow paging
        Public Overrides ReadOnly Property CanPage() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow sorting
        Public Overrides ReadOnly Property CanSort() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow updating
        Public Overrides ReadOnly Property CanUpdate() As Boolean
            Get
                Return False
            End Get
        End Property

    End Class

    ' A class to define a record of the data
    Public Class BookItem
        Private _id As String
        Private _title As String

        Public Sub New(ByVal id As String, ByVal title As String)
            _id = id
            _title = title
        End Sub

        Public ReadOnly Property ID() As String
            Get
                Return _id
            End Get
        End Property

        Public Property Title() As String
            Get
                Return _title
            End Get
            Set(ByVal value As String)
                _title = value
            End Set
        End Property
    End Class

    ' Custom designer for the CustomDataSource control.
    Public Class CustomDataSourceDesigner
        Inherits DataSourceDesigner

        Private _control As CustomDataSource = Nothing
        Private _defaultViewName As String = "BookList"
        Private _view As CustomDesignDataSourceView = Nothing

        Public Overrides Sub Initialize(ByVal cmponent As IComponent)
            MyBase.Initialize(cmponent)
            _control = CType(cmponent, CustomDataSource)
        End Sub

        ' Get a view
        Public Overrides Function GetView(ByVal viewName As String) As DesignerDataSourceView
            If Not (viewName.Equals(_defaultViewName)) Then
                Return Nothing
            ElseIf IsNothing(_view) Then
                _view = New CustomDesignDataSourceView(Me, _
                    _defaultViewName)
            End If

            Return _view
        End Function

        ' Get a list of view names
        Public Overrides Function GetViewNames() As String()
            Return New String() {"BookList"}
        End Function

        ' Don't allow refreshing the schema
        Public Overrides ReadOnly Property CanRefreshSchema() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow resizing
        Public Overrides ReadOnly Property AllowResize() As Boolean
            Get
                Return False
            End Get
        End Property
    End Class

    ' A     design-time data source view
    Public Class CustomDesignDataSourceView
        Inherits DesignerDataSourceView

        Private _data As ArrayList = Nothing

        Public Sub New(ByVal owner As CustomDataSourceDesigner, ByVal viewName As String)
            MyBase.New(owner, viewName)
        End Sub

        ' Get data for design-time display
        Public Overrides Function GetDesignTimeData( _
            ByVal minimumRows As Integer, _
            ByRef isSampleData As Boolean) As IEnumerable

            If IsNothing(_data) Then
                ' Create a set of design-time fake data
                _data = New ArrayList()
                Dim i As Integer
                For i = 1 To minimumRows
                    _data.Add(New BookItem("ID_" & i.ToString(), _
                        "Design-Time Title 0" & i.ToString()))
                Next
            End If
            isSampleData = True
            Return CType(_data, IEnumerable)
        End Function

        Public Overrides ReadOnly Property Schema() As IDataSourceViewSchema
            Get
                Return New BookListViewSchema()
            End Get
        End Property

        ' Allow getting the record count
        Public Overrides ReadOnly Property CanRetrieveTotalRowCount() As Boolean
            Get
                Return True
            End Get
        End Property
        ' Do not allow deletions
        Public Overrides ReadOnly Property CanDelete() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow insertions
        Public Overrides ReadOnly Property CanInsert() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow updates
        Public Overrides ReadOnly Property CanUpdate() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow paging
        Public Overrides ReadOnly Property CanPage() As Boolean
            Get
                Return False
            End Get
        End Property
        ' Do not allow sorting
        Public Overrides ReadOnly Property CanSort() As Boolean
            Get
                Return False
            End Get
        End Property
    End Class

    ' A custom View Schema class
    Public Class BookListViewSchema
        Implements IDataSourceViewSchema

        Public Sub New()
        End Sub

        ' The name of this View Schema
        Public ReadOnly Property Name() As String Implements IDataSourceViewSchema.Name
            Get
                Return "BookList"
            End Get
        End Property

        ' Build a Field Schema array
        Public Function GetFields() As IDataSourceFieldSchema() Implements IDataSourceViewSchema.GetFields
            Dim fields(1) As IDataSourceFieldSchema
            fields(0) = New CustomIDFieldSchema()
            fields(1) = New CustomTitleFieldSchema()
            Return fields
        End Function
        ' There are no child views, so return Nothing
        Public Function GetChildren() As IDataSourceViewSchema() Implements IDataSourceViewSchema.GetChildren
            Return Nothing
        End Function
    End Class

    ' A custom Field Schema class for ID
    Public Class CustomIDFieldSchema
        Implements IDataSourceFieldSchema

        Public Sub New()
        End Sub

        ' Name is ID
        Public ReadOnly Property Name() As String Implements IDataSourceFieldSchema.Name
            Get
                Return "ID"
            End Get
        End Property
        ' Data type is string
        Public ReadOnly Property DataType() As Type Implements IDataSourceFieldSchema.DataType
            Get
                Return GetType(String)
            End Get
        End Property
        ' This is not an Identity field
        Public ReadOnly Property Identity() As Boolean Implements IDataSourceFieldSchema.Identity
            Get
                Return False
            End Get
        End Property
        ' This field is read only
        Public ReadOnly Property IsReadOnly() As Boolean Implements IDataSourceFieldSchema.IsReadOnly
            Get
                Return True
            End Get
        End Property
        ' This field is unique
        Public ReadOnly Property IsUnique() As Boolean Implements IDataSourceFieldSchema.IsUnique
            Get
                Return True
            End Get
        End Property
        ' This field can't be longer than 20
        Public ReadOnly Property Length() As Integer Implements IDataSourceFieldSchema.Length
            Get
                Return 20
            End Get
        End Property
        ' This field can't be null
        Public ReadOnly Property Nullable() As Boolean Implements IDataSourceFieldSchema.Nullable
            Get
                Return False
            End Get
        End Property
        ' This is a Primary Key
        Public ReadOnly Property PrimaryKey() As Boolean Implements IDataSourceFieldSchema.PrimaryKey
            Get
                Return True
            End Get
        End Property

        ' These properties do not apply
        Public ReadOnly Property Precision() As Integer Implements IDataSourceFieldSchema.Precision
            Get
                Return -1
            End Get
        End Property
        Public ReadOnly Property Scale() As Integer Implements IDataSourceFieldSchema.Scale
            Get
                Return -1
            End Get
        End Property
    End Class

    ' A custom Field Schema class for Title
    Public Class CustomTitleFieldSchema
        Implements IDataSourceFieldSchema

        Public Sub New()
        End Sub

        ' Name is Title
        Public ReadOnly Property Name() As String Implements IDataSourceFieldSchema.Name
            Get
                Return "Title"
            End Get
        End Property
        ' Type is string
        Public ReadOnly Property DataType() As Type Implements IDataSourceFieldSchema.DataType
            Get
                Return GetType(String)
            End Get
        End Property
        ' This is not an Identity field
        Public ReadOnly Property Identity() As Boolean Implements IDataSourceFieldSchema.Identity
            Get
                Return False
            End Get
        End Property
        ' This field is not read only
        Public ReadOnly Property IsReadOnly() As Boolean Implements IDataSourceFieldSchema.IsReadOnly
            Get
                Return False
            End Get
        End Property
        ' This field is not unique
        Public ReadOnly Property IsUnique() As Boolean Implements IDataSourceFieldSchema.IsUnique
            Get
                Return False
            End Get
        End Property
        ' This field can't be longer than 100
        Public ReadOnly Property Length() As Integer Implements IDataSourceFieldSchema.Length
            Get
                Return 100
            End Get
        End Property
        ' This field can't be null
        Public ReadOnly Property Nullable() As Boolean Implements IDataSourceFieldSchema.Nullable
            Get
                Return False
            End Get
        End Property
        ' This is not the Primary Key
        Public ReadOnly Property PrimaryKey() As Boolean Implements IDataSourceFieldSchema.PrimaryKey
            Get
                Return False
            End Get
        End Property

        ' These properties do not apply
        Public ReadOnly Property Precision() As Integer Implements IDataSourceFieldSchema.Precision
            Get
                Return -1
            End Get
        End Property
        Public ReadOnly Property Scale() As Integer Implements IDataSourceFieldSchema.Scale
            Get
                Return -1
            End Get
        End Property
    End Class

End Namespace

<%@ Page Language="C#" %>
<%@ Register TagPrefix="aspSample" Namespace="ASPNet.Design.Samples_CS" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    <aspSample:CustomDataSource ID="CustomDS1" 
        runat="server"></aspSample:CustomDataSource>
    <asp:GridView ID="GridView1" runat="server"></asp:GridView>
    
    </div>
    </form>
</body>
</html>

<%@ Page Language="VB" %>
<%@ Register TagPrefix="aspSample" 
    Namespace="ASPNet.Design.Samples_VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    <aspSample:CustomDataSource runat="server" 
        ID="CustomDS1"></aspSample:CustomDataSource>
    <asp:GridView ID="GridView1" runat="server"></asp:GridView>
    
    </div>
    </form>
</body>
</html>

Comentários

A DataSourceDesigner classe é a classe base para designers de fonte de dados, como as SqlDataSourceDesignerclasses , AccessDataSourceDesignere ObjectDataSourceDesigner . Se você criar um novo controle de fonte de dados, talvez também queira criar um designer de controle personalizado para seu controle e derive-o da DataSourceDesigner classe .

A DataSourceDesigner classe tem dois métodos de evento: os OnDataSourceChanged métodos e OnSchemaRefreshed . Ambos os eventos podem ser temporariamente desabilitados com o SuppressDataSourceEvents método , que define a SuppressingDataSourceEvents propriedade . Os métodos de evento podem ser habilitados novamente com o ResumeDataSourceEvents método .

Há dois métodos estáticos que você pode usar para avaliar a equivalência de esquemas ou exibições sem criar uma instância da classe :

• O SchemasEquivalent método compara dois esquemas.

• O ViewSchemasEquivalent método compara os esquemas de duas exibições.

Notas aos Herdeiros

Para fornecer comandos para o menu de lista de ações em tempo de design em uma classe derivada, você deve substituir a ActionLists propriedade para retornar um objeto personalizado DesignerActionListCollection com itens personalizados derivados do DesignerActionList objeto .

Construtores

Propriedades

Métodos

Eventos

Implantações explícitas de interface

Aplica-se a

Confira também

• DataSourceControl
• Estendendo o suporte para tempo de design
• Como estender a aparência e o comportamento dos controles no modo de design